public static int main(String[] args) throws Exception {

    int i;
    String outPath;
    int numMaps = 0, numReds = 0;

    List<String> other_args = new ArrayList<String>();
    for (i = 0; i < args.length; ++i) {
      try {
        if ("-m".equals(args[i])) {
          numMaps = Integer.parseInt(args[++i]);
        } else if ("-r".equals(args[i])) {
          numReds = Integer.parseInt(args[++i]);
        } else {
          other_args.add(args[i]);
        }
      } catch (NumberFormatException except) {
        System.out.println("ERROR: Integer expected instead of " + args[i]);
        printUsage();
      } catch (ArrayIndexOutOfBoundsException except) {
        System.out.println("ERROR: Required parameter missing from " + args[i - 1]);
        printUsage(); // exits
      }
    }
    // Make sure there are exactly 2 parameters left.
    if (other_args.size() != 2) {
      System.out.println(
          "ERROR: Wrong number of parameters: " + other_args.size() + " instead of 2.");
      printUsage();
    }

    Date startTime = new Date();
    System.out.println("Job started: " + startTime);
    Date startIteration;
    Date endIteration;
    JobConf conf = new JobConf(Kmeans.class);
    conf.setJobName("kmeans");
    conf.setOutputKeyClass(IntWritable.class);
    conf.setOutputValueClass(Text.class);
    conf.setMapOutputKeyClass(IntWritable.class);
    conf.setMapOutputValueClass(ClusterWritable.class);
    conf.setMapperClass(MapClass.class);
    conf.setReducerClass(Reduce.class);
    conf.setNumMapTasks(numMaps);
    conf.setNumReduceTasks(numReds);
    FileInputFormat.setInputPaths(conf, new Path(other_args.get(0)));
    outPath = new String(other_args.get(1));
    FileOutputFormat.setOutputPath(conf, new Path(outPath));
    startIteration = new Date();
    JobClient.runJob(conf);
    endIteration = new Date();
    System.out.println(
        "The iteration took "
            + (endIteration.getTime() - startIteration.getTime()) / 1000
            + " seconds.");
    return 0;
  }
  public void reduce(
      Text key, Iterator<Text> values, OutputCollector<Text, Text> output, Reporter reporter)
      throws IOException {
    List<String[]> _temp = new ArrayList<String[]>();
    int count = 0;
    while (values.hasNext()) {
      Text _out = values.next();
      String[] tokens = StringUtils.splitPreserveAllTokens(_out.toString(), TAB);
      _temp.add(tokens);
      if (count++ > 100000) break;
    }

    if (count > 10000) {
      Set<String> ipSet = new HashSet<String>();
      for (int posI = 0; posI < _temp.size(); posI++) {
        String[] array = _temp.get(posI);
        if (array == null) continue;

        String mid = array[2];
        String ip = array[3];
        ipSet.add(ip);
      }
      output.collect(
          key, Utils.mergeKey(String.valueOf(ipSet.size()), StringUtils.join(ipSet, '|')));
      return;
    }

    /**
     * ·Ö×éËã·¨ FOREACH ALL_DATA IF IN INDEX THEN UPDATE INDEX AND INSERT DATA ELSE FOREACH SUB_DATA
     * MAKE INDEX AND SET FIND'S DATA AS NULL
     */
    // List<List<String[]>> dataList = new ArrayList<List<String[]>>();
    List<StringBuffer> indexList = new ArrayList<StringBuffer>();
    Set<String> ipSet = new HashSet<String>();
    boolean muliHost = false;
    for (int posI = 0; posI < _temp.size(); posI++) {
      String[] array = _temp.get(posI);
      if (array == null) continue;

      String mid = array[2];
      String ip = array[3];
      ipSet.add(ip);
      boolean hasIndex = false;
      for (int i = 0; i < indexList.size(); i++) {
        StringBuffer index = indexList.get(i);
        if (index.indexOf("|" + mid + "|") >= 0 || index.indexOf("|" + ip + "|") >= 0) {
          if (index.indexOf("|" + mid + "|") < 0) {
            index.append('|').append(mid).append('|');
          }

          if (index.indexOf("|" + ip + "|") < 0) {
            index.append('|').append(ip).append('|');
          }
          // dataList.get(i).add(array);
          hasIndex = true;
          break;
        }
      }
      if (!hasIndex) {
        StringBuffer index = new StringBuffer("|" + mid + "|" + ip + "|");
        // List<String[]> _tmp = new ArrayList<String[]>();
        // _tmp.add(array);
        for (int k = posI + 1; k < _temp.size(); k++) {
          String[] _newArray = _temp.get(k);
          if (_newArray == null) {
            continue;
          }
          String _mid = _newArray[2];
          String _ip = _newArray[3];
          if (index.indexOf("|" + _mid + "|") >= 0 || index.indexOf("|" + _ip + "|") >= 0) {
            if (index.indexOf("|" + _mid + "|") < 0) {
              index.append('|').append(_mid).append('|');
            }

            if (index.indexOf("|" + _ip + "|") < 0) {
              index.append('|').append(_ip).append('|');
            }
            // _tmp.add(_newArray);
            _temp.set(k, null);
          }
        }
        indexList.add(index);
        // dataList.add(_tmp);
      }
    }
    //        for(String[] _array : _temp){
    //            output.collect(key,Utils.mergeKey(_array[1],_array[2],_array[3],_array[4]));
    //        }

    StringBuffer allIndex = new StringBuffer();
    for (StringBuffer index : indexList) {
      allIndex.append(index).append(';');
    }
    if (allIndex.length() > 0) {
      allIndex.deleteCharAt(allIndex.length() - 1);
    }
    output.collect(
        key, Utils.mergeKey(String.valueOf(indexList.size()), StringUtils.join(ipSet, '|')));
  }